Field of the Invention
This invention relates to generally to wound healing. In particular, the invention relates to wound healing with pressures altered both positively and negatively from atmospheric.
More specifically this invention is directed at apparatuses and methods that utilize Altered Pressures which are more convenient, safe and efficient for the clinician, more comfortable and less painful for the patient, and result in improved efficacy versus those of the prior art.
Background of the Invention
The need to rapidly close acute and chronic wounds has been a focus of research since the dawn of medical practice. The background art is characterized by therapeutic strategies utilizing pressures altered from atmospheric conditions. Such strategies have been practiced by clinicians for both acute and chronic wounds for over a hundred years. Positive pressure strategies began expanded utilization least by the early 1800's, while negative pressure wound therapy began institutional practice at least as far back as the early 1980's.
Positive pressure wound therapy began by employing large chambers that encapsulated the entire patient. While more locally focused pressures have been attempted, they proved problematic for the relatively high pressures utilized. Conversely, to date negative pressure wound therapy has been developed as a local site methodology, specific to a peripheral zone around the wound bed. Likewise, the present invention limits its application to the local tissue of and around the wound; however, it utilizes both negative pressures and positive pressures.
The following core features are common among the negative pressure wound therapy configurations known in the art which employ a local site application methodology:                a covering means adapted to protect a wound from contamination and/or trauma;        a sealing means, optionally designed as a part of the covering means, for establishing intimate but reversible contact with the perimeter of said covering to surrounding skin surfaces of said wound, thereby creating an Encapsulated Space, including the wound bed under said covering;        the sealing means further providing a seal competent enough to provide treatment of the wound with pressures purposefully altered to those lower than atmospheric;        a pressure altering means for interfacing negative pressures from a source with the said Encapsulated Space to lower the pressure therein as desired, said pressure altering means working in combination with said covering and sealing means to maintain the so desired Encapsulated Space pressures;        the pressure altering means comprising a Proximal end, a Medial section and a Distal end;        a negative pressure source for delivering the initial pressure differential to the pressure altering means; and optionally at least one of the following:                    a. the pressure altering means further consisting of a Proximal end with direct physical access to the Encapsulated Space through an opening or conduit through said covering, and a Distal end connected to the Proximal end via a Medial section, such Distal end further adapted for connection to a negative pressure source; or            b. the pressure altering means further consisting of a Proximal end with direct physical access to the Encapsulated Space through a passage created between skin and sealing means of said covering, and a Distal end connected to the Proximal end via a Medial section, such Distal end further adapted for connection to a negative pressure source; or            c. the pressure altering means further consisting of a Proximal end with indirect access to the Encapsulated Space though a void or opening in said cover, and a Distal end connected to the Proximal end via a Medial section, such Distal end further adapted for connection to a negative pressure source; or            d. the pressure altering means further consisting of a Proximal end with indirect access to the Encapsulated Space through a passage created between skin and sealing means of said covering, and a Distal end connected to the Proximal end via a Medial section, such Distal end further adapted for connection to a negative pressure source.                        
The apparatus above generically encompasses the core features of the historical apparatuses in the literature and prior art.
Related Art
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention; however, the following references were considered related.
Journal article “The vacuum effect in the surgical treatment of purulent wounds” by Kostiuchenok, I I; Kolker, V A Karlov V A, et al.: Vestnik Khirurgii 1986 describes an intermittent manual application of minimal negative pressure to reduce bacterial counts and heal stubborn wounds.
Journal article “Vacuum therapy of acute supporative diseases of soft tissues and suppurative wounds” by Davydov IuA, Larichev A B, Smirnov A P: Vestnik Khirurgii Imeni i—i.—Grekova 1986 presents the retrospective results of over 100 patients presenting with purulent mastitis. The authors describes the techniques of intermittent application of various negative pressures and durations as used in their clinic since 1980, as well as efficacy results regarding these techniques.
Journal article “Active wound drainage” by Usupov, Y N; Yepifanov, M V: Vestnik Khirugii 1987 describes the authors methodology and results for determining apparent threshold and maximum negative pressures which attempt to project a therapeutic index for negative pressures from an animal model.
Journal article “Bacteriologic and cytologic evaluation of vacuum therapy of suppurative wounds” by Davydov IuA, Larichev A B, Men'kov K G: Vestnik Khirurgii Imeni—i—Grekova 1988 describes the techniques for intermittent application of various negative pressures and durations and demonstrates the faster progression through healing stages of these patients compared to controls.
Journal article “Effective management of incisional and cutaneous fistulae with closed suction wound drainage” by Chariker, M E; Jeter, K F, et al.: Contemporary Surgery 1989 authors describe specific dressings and treatment methodologies including drains, screens, packings and covers which are readily available to world wide clinicians and readily adaptable to negative pressure therapy. The authors report on the training and efficacy of these methodologies for a specific hard to heal surgical wounds, namely fistulae complicated wounds.
Journal article “Concepts for clinical biological management of the wound process in the treatment of purulent wounds using vacuum therapy” by Davydov, Y A; Larichev, A B, Abramov A Y, et al.: Vestnik Khirugii 1991 authors report on expansion of applications of negative pressure techniques to various acute and chronic wounds as well as patient populations as expanded since their previous publication. Authors also describe attributes of negative pressure therapy that may explain its efficacy.
U.S. Pat. No. 4,969,880 issued in the name of Zamierowski; David S. teaches the composition of a wound dressing designed for negative pressure treatment of a wound that includes a semi-permeable cover with an adhesive sealing means, an opening formed through the cover for the introduction of a PAM said PAM adapted for connection to a negative pressure source or a fluid source for introducing fluids and Intermediate Materials placed between the wound and the cover. A method of wound treatment with the teachings of the dressing is also disclosed.
U.S. Pat. No. 5,645,081 issued in the name of Argenta et al. teaches another method for wound treatment utilizing negative pressure, but utilizes an impermeable cover rather than semi-permeable, contrary to U.S. Pat. No. 4,969,880. The patent further teaches the use of Intermediate Materials with impermeable covers with the PAM contained within or underneath the Intermediate Materials.
U.S. Pat. No. 5,636,643 issued in the name of Argenta et al. teaches another method for wound treatment utilizing negative pressure, but utilizes an impermeable cover rather than semi-permeable, contrary to U.S. Pat. No. 4,969,880. The patent further teaches the use of negative pressure adapted to specific wound types and specific durations of therapy.
U.S. Pat. No. 6,135,116 issued in the name of Vogel et al. teaches a method and apparatus for combining intermittent pneumatic compression and negative pressure wound therapy.
U.S. Pat. No. 6,553,998 issued in the name of Heaton et al. teaches negative pressure wound therapy that utilizes the combination of a suction head and a cover. More specifically, the suction head is designed with projections on the bottom flange which prevent sealing or blockage of the suction head by providing flow channels for liquids to exit the wound via a PAM.
Consequently, a need has been demonstrated for the invention which provides methods, apparatuses and compositions that: (a) improve the performance of Altered Pressure wound therapy (b) make the treatments more comfortable for the patient, and (c) make the administration of the treatment more convenient for clinicians. These improvements collectively result in improved efficacy, improved compliance, improved safety and improved clinical efficiency, while limiting clinical errors in treatment.